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240 Landmarks of Japanese Automotive Technology
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240 Landmarks TopMotorcycles > Yamaha 125YA-1
 Yamaha 125YA-1
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This model was Yamaha's first motorcycle and the starting point for Yamaha Motor Co. Ltd.
It attracted much attention in 1955 by monopolizing the top ranks in the Mt. Fuji Hill Climb and the Mt. Asama race. The high-quality finish and outstanding race performance led it to be affectionately called the "Red Dragonfly" by Japanese motorcycle lovers, due to its thin body and chestnut brown tank.
This was the first vehicle in Japan to utilize the primary starting method.
Before this method was adopted, motorcycles had a structure in which the main axle was turned by the kick gear via the transmission gear. Therefore, it was necessary to kick without releasing the clutch, making sure to set the transmission to the neutral position before the engine was started.
With the primary kick-starting system, the motorcycle is equipped with a mechanism in which the primary driven gear (a large speed-reducing gear) is turned by means of a kick idling gear and kick pinion. This enables the engine to start regardless of the position of the transmission gear once the clutch was released. This mechanism is now extremely popular.
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Storage location:YAMAHA COMMUNICATION PLAZA (2500, Shingai, Iwata-shi, Shizuoka-ken 438-8501)
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Year manufactured:1955
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Manufacturer:Nippon Gakki Co., Ltd.
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Classification:Mass-production vehicle
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Current status:On public display: static
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Vehicle name / Manufacture
Vehicle name:Yamaha 125
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Model:YA-1
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Company name:Nippon Gakki Co., Ltd.
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Vehicle type/usage:On-road sports bike
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Location of actual vehicle/replica:Communication Plaza
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Year manufactured:1955
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Designed by:Nippon Gakki Co., Ltd.
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Model / Weight
Style:Sports
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Passenger capacity:2
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Weight:105.5 kg
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Front axle weight:46 kg
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Rear axle weight:59.5 kg
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Points of interest, topicality:The first motorcycle by Yamaha Motor Co., Ltd., monopolized the top ranks in the Mt. Fuji Hill Climb and the Mt. Asama race.
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Body / Size
Overall length:1980 mm
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Overall width:660 mm
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Overall height:925 mm
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Headlamp type:6 V, 25 W
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Tire size (front):2.75-19-2P
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Tire size (rear):2.75-19-4P
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Body / Axle / Driving / Others
Suspension type (front):Coil spring
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Suspension type (rear):Coil spring
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Wheelbase:1290 mm
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Brakes (front):Internal expanding hand brake
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Brakes (rear):Internal expanding foot brake
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Engine/ Size / Power
Type:Air-cooled 2-stroke
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Cylinder arrangement:Single cylinder
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Carburetor:AMAL M20
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Bore x stroke:52×58 mm
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Displacement:123 cc
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Ignition system:Ignition dynamo
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Max. power/r.p.m.:5.5 hp/5000 rpm
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Lubrication method:Mixed lubrication
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Start method:Kick
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Fuel tank capacity:9.5 L
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Drive-train
Transmission:Constant-mesh type 4 forward speeds
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Power transmission method:Gear/chain
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Clutch type:Wet multiple disc type
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Performance
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